Fill in the blanks.
The ratio of the number of girls to the number of boys in Class A is 9 : 5.
The ratio of the number of girls to the number of boys in Class B is 2 : 7.
The number of girls is the same.
- Number of girls in Class A = _____ u
- Number of boys in Class B = _____ u
- Number of children in Class B = _____ u
- Total number of children = _____ u
Class A |
Class B |
Girls |
Boys |
Girls |
Boys |
9 x 2 |
5 x 2 |
2 x 9 |
7 x 9 |
18 u |
10 u |
18 u |
63 u |
(a)
Change ratio into units.
The number of girls in Class A and Class B is the same.
LCM of 9 and 2 = 18
Class A
Girls : Boys
9 : 5
(x2) 18 : 10
Class B
Girls : Boys
2 : 7
(x9) 18 : 63
Number of girls in Class A = 18 u
(b)
Number of boys in Class B = 63 u
(c)
Number of children in Class B
= 18 u + 63 u
= 81 u
(d)
Number of children in Class A
= 18 u + 10 u
= 28 u
Total number of children
= 81 u + 28 u
= 109 u
Answer(s): (a) 18; (b) 63; (c) 81; (d) 109